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TitleExtending the terrestrial depositional record of marine geohazards near Kitimat, coastal northwest British Columbia
 
AuthorHuntley, DORCID logo; Bobrowsky, PORCID logo; Lintern, GORCID logo
SourceResources for Future Generations, conference abstracts volume; 1912, 2018 p. 1
Year2018
Alt SeriesNatural Resources Canada, Contribution Series 20180459
MeetingRFG2018 - Resources for Future Generations; Vancouver, BC; CA; June 16-21, 2018
DocumentWeb site
Lang.English
Mediapaper; digital; on-line
File formatdocx
ProvinceBritish Columbia
NTS103H/15; 103I/02
AreaKitimat; Kitimaat Village; Hartley Bay; Douglas Channel
Lat/Long WENS-129.0000 -128.5000 54.2500 53.7500
Subjectsmarine geology; surficial geology/geomorphology; structural geology; landslides; slope failures; slumps; tsunami; coastal environment; marine sediments; salt marshes; organic deposits; peat; soils; bedrock geology; structural features; fractures; storms; depositional environment; modelling; geological hazards; tsunami deposits; Phanerozoic; Cenozoic; Quaternary
ProgramPublic Safety Geoscience, Marine Geohazards
Released2018 06 01
AbstractEarthquakes, landslides tsunamis, storms and floods challenge the development of safe, resilient communities and supporting infrastructure on Canada's west coast. At present, vulnerability assessments, land use plans and infrastructure designs are hindered by significant gaps in the geological record of geohazards in coastal British Columbia. Our study examines salt marsh peat deposits and forest soils near the communities of Kitimat, Kitimaat and Hartley Bay. Detailed analyses of sedimentology, radiocarbon dates, fossils, and geochemistry build on the provisional description of terrestrial soils presented here to establish a postglacial record of tsunami, storm and flood events spanning much of the Holocene. Small volume debris slides and rock falls do not generate tsunamis of any consequence. Marine sediments deposited beyond storm berms at the fjord head are a record of local tsunamis generated by submarine slumps at the head of Douglas Channel, where shallow water (<100 m) amplifies the tsunamigenic potential of failing sediment and displaced water mass. Deep-fractured bedrock mapped upslope from relict submarine features could trigger damaging tsunami waves if rapid failure into the fjord were to occur. Geological records of ancient large volume rock-slope failures were not preserved in the high-energy post-glacial marine environment. Newly discovered marine inundation deposits provide physical confirmation of numerical models and suggest that Pacific-sourced storms and seismic tsunamis expend much of their energy in the outer coast and rarely reach far up the mainland fjords. Only great earthquakes, large landslides, submarine slumps and seasonal storms above certain threshold volumes and impulse energy produce geomorphically significant inundation events. This extended record will constrain modelling of future geohazard events, thereby reducing development risks in north coastal British Columbia.
Summary(Plain Language Summary, not published)
Our study examines salt marsh peat deposits and forest soils near the communities of Kitimat, Kitimaat and Hartley Bay. Detailed analyses of sedimentology, radiocarbon dates, fossils, and geochemistry build on the provisional description of terrestrial soils presented here to establish a postglacial record of tsunami, storm and flood events spanning much of the Holocene. This extended record will constrain modelling of future geohazard events, thereby reducing development risks in north coastal British Columbia.
GEOSCAN ID314572

 
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